9. Lead Deposit Removal
A. Refer to the sections “Grit-Blast Media” and “Grit-Blast Procedure” in this chapter:
(1) If Non-Destructive Testing is not to be done on the component, grit-blast (the component
with lead deposits) with 17 grit walnut shells or equivalent at 35 to 45 psi (241 to 310 kPa).
(2) If Non-Destructive Testing is to be done on the component, use a fine abrasive of 150-grit
or finer.
B. Remove all debris from the component to prevent problems caused by foreign object debris.
10. Volcanic Ash Removal
CAUTION IF VOLCANIC ASH IS SUSPECTED ON THE ENGINE, DO NOT INHALE IT
OR TOUCH IT WITH BARE HANDS OR GET IT IN YOUR EYES. WEAR
PERSONAL PROTECTIVE EQUIPMENT. DO NOT USE WATER TO RINSE
IT OFF. THE VOLCANIC ASH CAN CONTAIN ACIDIC COMPOUNDS
WHICH MUST NOT BE INHALED OR TOUCHED SINCE IT CAN CAUSE
INJURY.
A. Engine exterior and components NOT contaminated with volcanic ash:
(1) Remove grease, oil, dirt, and soft carbon deposits from the parts.
(2) Spray or brush the components with a hydrocarbon-base solvent.
B. To remove volcanic ash:
(1) Wear personal protective equipment (gloves, respiratory, and eye protection).
(2) Per the aircraft manufacturer’s instructions, thoroughly remove the ash or particulate
from the aircraft by hand brushing or air/vacuuming. Make sure that all ash is removed
from the engine and cowling.
C. Examine the induction filters, induction system, and engine baffles for blockage or damage.
D. Refer to the section “Volcanic Ash/Particulate Contamination” in Chapter 05-50 for further
details.
E. Refer to the aircraft manufacturer’s instructions for additional information
11. Cleaning Guidelines for a Soaked Engine
A. Clean the engine, especially all recessed areas where debris and silt can get trapped.
B. When cleaning parts removed from an engine that was soaked, especially ferrous (iron)
metals, do not use hot acidic cleaning agents or electrolytic cleaning methods (such as
cathodic cleaning) since they can cause hydrogen embrittlement. This embrittlement can
cause a metallic part to weaken and fail.
C. Additionally, acids can generally attack the metals and cause pitting or other corrosion
damage.
D. Be sure to remove all cleaning agents.
E. Rinse the part thoroughly.
F. Dry the part.
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